This invention relates to compact hand held vacuum cleaners of the type in which a replaceable filter bag is mounted with its closed end extending in the upstream direction of airflow within a tapered hood or "dust cup," the vacuum nozzle for the cleaner being at the intake end of the dust cup and the dust cup being detachable from the remainder of the cleaner for emptying from its large rearward or downstream end. Such cleaners are also provided with a flap valve associated with the vacuum nozzle to prevent dirt from falling out of the dust cup if power is turned off with the cleaner pointed downwardly--the normal attitude during use.
Hand held vacuum cleaners of the foregoing dust cup type have previously been provided, and have gained wide market acceptance. Earlier units had separate nozzle structure outside the upstream end of the dust cup, as in U.S. Pat. No. 3,513,500. Later units had a nozzle located at the upstream or forward end of the dust cup itself, as in U.S. Pat. No. 4,209,875, with the tapering of the dust cup extending all the way to the relatively narrow forward end at which the nozzle is located, and with a flap valve immediately behind the nozzle. This simple arrangement is effective, but convenience of use is limited by the fixed relationship between the nozzle on the one hand and the elongated assembly formed by the cleaner body and dust cup on the other hand. Thus, when trying to clean horizontal surfaces at a high location or vertical surfaces near the floor, it can be very awkward for the user to properly align the nozzle for effective cleaning of the surface. Rather than pointing the cleaner in a downwardly tilted direction in order to properly align the nozzle, as is normally done, it would be far more convenient in many instances (say when the cleaner is being used on a horizontal surface near the eye level of the user) to manipulate the cleaner while holding it in a horizontal attitude if proper nozzle alignment could be maintained.
Hand held vacuum devices have been proposed which are provided with flexible but positionally stable tubular connection of small cross sectional area between the collecting receptacle and a separate nozzle, as in U.S. Pat. No. 4,175,352, which is not of the type employing a separable dust cup, and is employed for insect collection rather than vacuum cleaning. However, no practical nozzle tilting arrangement with adequate cross section area has been developed for hand held vacuum cleaners of the dust cup type, even for those of the older constructions which had a separate nozzle. Constraints as to length of the cup-to-nozzle connection and minimal cross-sectional area for adequate vacuuming action make the use of a flexible but positionally stable tube impractical. And for dust cup type cleaners of the newer construction, in which the nozzle is located at the upstream end of the dust cup itself, there are not believed to have been any suggestions whatsoever regarding provision of a tilt nozzle or practical means to accomplish the same.